18370-11-1

Herein, we report a simple and efficient method for the direct installation of chlorodifluoroethyl group onto aromatic molecules of various aromatic amides with a new 2-chloro,2,2-difluoroethyl(mesityl)iodonium salt (CDFI). Moreover, the chlorodifluoroeth

Here, a photocatalytic deoxygenative amidation protocol using readily available amine-boranes and carboxylic acids is described. This approach features mild conditions, moderate-to-good yields, easy scale-up, and up to 62 examples of functionalized amides with diverse substituents. The synthetic robustness of this method was also demonstrated by its application in the late-stage functionalization of several pharmaceutical molecules.

In this work we studied the reactivity of the Trifluoroacetic acid hydroxylamine system in the one step salt free synthesis of amides from ketones. A particular regards was paid to the caprolactam synthesis because of its industrial relevance. Synthesis, reactivity and characterization of the hydroxylamine trifluoroacetate is given. Fast oximation reaction of several ketones was gained at room temperature (1?h of reaction quantitative conversion for several ketones). In the same reactor, by raising the temperature at 383?K, the Beckmann rearrangement of the so obtained oximes is easily accomplished in the presence of three equivalent of TFA. The possibility of obtaining the trifluoroacetate of the hydroxylamine with a modified nitric acid hydrogenation reactions was verified, too. Reuse of solvent and trifluoroacetic acid is easily achieved by distillation. Graphical abstract: Salt free one-pot caprolactam and amides process catalyzed by CF3COOH, in the presence of NH2OH TFA as the oximation agent.[Figure not available: see fulltext.].

Host-guest assemblies of a designed 1,4-bis(diarylamino)naphthalene and V-shaped aromatic amphiphiles consisting of two pentamethylbenzene moieties bridged by an m -phenylene unit bearing two hydrophilic side chains emerged as highly reducing photoredox catalysis systems in water. An efficient demethoxylative hydrogen transfer of Weinreb amides has been developed. The present supramolecular strategy permits facile tuning of visible-light photoredox catalysis in water.

An efficient enantioselective [3+2] cycloaddition of isomünchnones with methyleneindolinones that are generated by anin situintramolecular addition of the carbonyl group to rhodium carbenes is realized with a chiralN,N′-dioxide/Zn(ii) complex as a Lewis acid. A series of chiral oxa-bridged 3-spiropiperidines are obtained in high yields with excellent dr and excellent ee values.

An unprecedented N-demethylation of N-methyl amides has been developed by use of N-fluorobenzenesulfonimide as an oxidant with the aid of a copper catalyst. The conversion of amides to carbinolamines involves successive single-electron transfer, hydrogen-atom transfer, and hydrolysis, and is accompanied by formation of N-(phenylsulfonyl)benzenesulfonamide. Carbinolamines spontaneously decompose to N-demethylated amides and formaldehyde, because of their inherent instability.

Metal-catalyzed chelation-assisted C?H olefinations have emerged as powerful tools for the construction of functionalized alkenes. Herein, we describe the rhoda-electrocatalyzed C?H activation/alkenylation of arenes. The olefinations of challenging electron-poor benzamides were thus accomplished in a fully dehydrogenative fashion under electrochemical conditions, avoiding stoichiometric chemical oxidants, and with H2 as the only byproduct. This versatile alkenylation reaction also features broad substrate scope and used electricity as a green oxidant.

Lewis acid-assisted palladium-catalysed dealkoxylation ofN-alkoxyamides has been developed. This reaction proceeded smoothly with a range ofN-alkoxyamides in the absence of an external reductant, thereby establishing a convenient and reductant-free protocol. In addition, a gram-scale reaction could be achieved. Preliminary mechanistic investigations indicated that β-hydrogen elimination from a palladium alkoxide intermediate generated an intramolecular hydride source.

Reported is an iridium catalyst for ortho-selective C?H borylation of challenging secondary aromatic amide substrates, and the regioselectivity is controlled by hydrogen-bond interactions. The BAIPy-Ir catalyst forms three hydrogen bonds with the substrate during the crucial activation step, and allows ortho-C?H borylation with high selectivity. The catalyst displays unprecedented ortho selectivities for a wide variety of substrates that differ in electronic and steric properties, and the catalyst tolerates various functional groups. The regioselective C?H borylation catalyst is readily accessible and converts substrates on gram scale with high selectivity and conversion.

The [4 + 1] annulation of benzamides and aldehydes for phthalide synthesis was achieved via rhenium-catalyzed C-H activation, which demonstrates an unprecedented reaction pattern distinct from those of other transition-metal catalyses. The reaction also features readily available starting materials, a wide scope for both electro-rich and electro-deficient substrates, and the elimination of homoannulation byproducts.

Isocyanates are useful building blocks for the synthesis of amides, although their widespread use has been limited by their high reactivity, which often results in poor functional group tolerance and a propensity to oligomerize. Herein, a rhodium-catalyzed synthesis of amides is described coupling boroxines with blocked (masked) isocyanates. The success of the reaction hinges on the ability to form both the isocyanate and the organorhodium intermediates in situ. Relying on masked isocyanate precursors and on the high reactivity of the organorhodium intermediate results in broad functional group tolerance, including protic nucleophilic groups such as amines, anilines, and alcohols.

Tandem conversion of aldoximes to N-methylated amides with methanol in presence of a single Ru(II) catalyst is accomplished through the Ru(II)-mediated rearrangement followed by the reductive N-methylation. Employing this protocol, several aldoximes were directly transformed to the N-methylated amides using methanol. Kinetic experiments with H218O advocated that the aldoxime is acted as the nucleophile during the aldoxime to amide rearrangement process. Involvement of nitrile intermediate during this transformation is realized from the kinetic study. (Figure presented.).

A cobalt complex catalyzed tandem conversion of nitrile to N-methylated amide is described using a methanol and water mixture. Using this protocol, several nitriles were directly and efficiently converted to the desired N-methylated amides. Kinetic experiments using H2O18 and CD3OD suggested that water and methanol were the source of the oxygen atom and methyl group, respectively, in the final N-methylated amides. Importantly, the participation of active Co(I)-H species in this transformation was realized from the control experiment. The kinetic isotope effect (KIE) study suggested that the activation of the C-H bond of methanol was a kinetically important step. The Hammett plot confirmed that the reaction was faster with the electron deficient nitriles. In addition, the plausible pathway for the formation of N-methylated amides from the nitriles was supported by the computational study.

An efficient synthesis of N-methylated amides using methanol in the presence of a ruthenium(II) catalyst is realized. Notably, applying this process, tandem C-methylation and N-methylation were achieved to synthesize α-methyl N-methylated amides. In addition, several kinetic studies and control experiments with the plausible intermediates were performed to understand this novel protocol. Furthermore, detailed computational studies were carried out to understand the mechanism of this transformation.

A nickel-catalyzed aminocarbonylation of aryl halides using carbamoylsilane as an amide source leading to corresponding secondary or primary aromatic amides has been developed, in which the methoxymethyl and benzyl were used as amino protecting group. The protocol tolerates a broad range of aryl halides bearing different functional groups to afford good yields of aryl amides under mild reaction conditions. The types and the relative positions of substituents on the aryl ring make a notable impact on the coupling efficiency. The plausible mechanism of nickel-catalyzed aminocarbonylation has been suggested.

Conversion of a wide range of N-Boc amides to aryl ketones was achieved with Grignard reagents via chemoselective C(O)-N bond cleavage. The reactions proceeded under catalyst-free conditions with different aryl, alkyl, and alkynyl Grignard reagents. α-Ketoamide was successfully converted to aryl diketones, while α,β-unsaturated amide underwent 1,4-addition followed by C(O)-N bond cleavage to provide diaryl propiophenones. N-Boc amides displayed higher reactivity than Weinreb amides with Grignard reagents. A broad substrate scope, excellent yields, and quick conversion are important features of this methodology.

Surface-modified polymer compositions are provided. The surface-modified polymer compositions can include a polymer and a multifunctional linker. The surface-modified polymer compositions can include a polymer, a multifunctional linker, and a surface group. Aqueous-based processes can be used to fabricate the surface-modified polymer compositions.

Surface-modified polymer compositions are provided. The surface-modified polymer compositions can include a polymer and a multifunctional linker. The surface-modified polymer compositions can include a polymer, a multifunctional linker, and a surface group. Aqueous-based processes can be used to fabricate the surface-modified polymer compositions.

A highly selective and easily handled monoalkylation of primary amide derivatives by using trialkyl phosphates as alkylating reagents in cyclopentyl methyl ether (CPME) was developed. Various monoalkylated amide derivatives were efficiently synthesized by changing the alkyl moiety (e.g., methyl, ethyl, butyl, or benzyl) of the trialkyl phosphate. These phosphate reagents are relatively stable and easily available, and CPME is a useful solvent in process chemistry.

The use of a dual palladium/organic photoredox catalytic system enables the directed arylation of arenes with aryldiazonium salts with a broad substrate scope at room temperature under mild reaction conditions. This study thus serves as not only an alternative route for the biaryl motifs but also a new example for the application of an organic photoredox catalyst.

A simple and direct C-H trifluoroethylation of aromatic amides has been developed. The protocol is applicable to a variety of aromatic amides, including ones derived from amino acids. The developed method can be used for further modifications of peptides. Preliminary mechanistic studies have been done by isolating the reaction intermediate.

We report a novel and efficient method for the oxidation of benzylic carbons (amines and cyanides) into corresponding benzamides using a catalytic amount of I2 and TBHP as the green oxidant via the C-H bond cleavage of the benzylic carbon under mild reaction conditions. According to the literature survey, this is the first report for the oxidative amidation of benzylamines and decyanation of benzyl cyanides in one pot under metal-free conditions.

Using N-methoxymethyl-N-organylcarbamoyl(trimethyl)silanes as secondary amides source, the direct transformation of aryl halides into the corresponding secondary aromatic amides via palladium-catalyzed aminocarbonylation is described. The reactions tolerated a broad range of functional groups on the aryl ring except big steric hindrance of substituent. The types and the relative position of substituents on the aryl ring impact the coupling efficiency.

The nickel-catalyzed aminocarbonylation of aryl halides using carbamoylsilane as an amide source is developed. The procedure can prepare both tertiary and secondary amides, and is applicable to various carbamoylsilanes and aryl halides containing differen

A highly effective oxidative thiyl radical addition/cyclization of N-methacryloylbenzamides was explored using dioxygen as the sole terminal oxidant without the use of precious and/or toxic transition-metal catalysts. This method provides convenient access to a variety of useful sulfide-containing 4,4-disubstituted isoquinoline-1,3-diones by constructing C-S and C-C bonds in one step.

Pd(0)-mediated 11C-carbonylation of aryl(mesityl)iodonium salts followed by suitable quench provides a rapid room-temperature two-pot procedure for labeling arylcarboxylic acids and amide derivatives with the short-lived positron emitter carbon

We present a metal-free method for the synthesis of imides by the direct coupling of NH-amides with methylarenes under iodine/aqueous TBHP conditions. The optimized conditions worked very well with benzaldehydes and benzyl alcohol and furnished the corresponding imides in good to excellent yields. A series of control and radical scavenger experiments were also performed, which suggested the involvement of radical pathways. The labeling experiment in the presence of 18O-labeled H2O suggested water as a source of oxygen in the imides.

A metal–organic framework (MOF) based on copper and 1,3-bis(carboxymethyl)imidazole (bcmim) was prepared on a gram scale by using a precipitation method at room temperature. The Cu(bcmim)2MOF was shown to be an efficient catalyst for the preparation of amides through an oxidative coupling between carboxylic acids and formamides in the presence of an oxidant, such as tert-butyl hydroperoxide (TBHP). The method for the preparation of the amides is robust regardless of the carboxylic acid and gives good conversions with good selectivity. The heterogeneous catalyst was recovered unaltered after the reaction, was easily separated from the reaction mixture, and subsequently reactivated by suitable treatment. Moreover, the coupling reaction was scaled up to a gram scale, which allowed for the preparation of valuable products, such as fatty acid amides (i.e., 1-palmitoylpiperidine).

The cobalt(III)-catalyzed allylation was developed for amide-directed C-H activation of arenes, heteroarenes, and olefins. A variety of allyl sources can be employed to introduce this useful functional group.

As a result of our recent investigations into the N-functionalization of sulfoximines, an iron-catalyzed dealkylative acylation of N-alkylsulfoximines has been developed. This process involves a Polonovski-type dealkylation of an N-alkylated sulfoximine to afford a reactive intermediate that is trapped in the presence of a suitable aldehyde or anhydride to afford N-acyl- and N-aroylsulfoximine derivatives in one pot. Subsequent cleavage of the acyl or aroyl group under acidic conditions generates a synthetically valuable NH-sulfoximine. The dealkylation of N-alkylsulfoximines has been developed utilizing TBHP as oxidant and a catalytic amount of iron chloride to furnish a range of N-acyl- and N-aroylsulfoximines. This method facilitates the use of N-alkyl protecting groups that provide very stable N-protected sulfoximine derivatives that can be readily modified at sites other than the nitrogen atom.

Study of safeners has been seldom reported in literature. In this work, a series of novel acylsulfamoylbenzamide analogues was designed and synthesized with newly developed safener cyprosulfamide (CSA) as the leading compound. The activity assay against the herbicide thiencarbazone-methyl (TCM) on maize revealed that fifteen compounds showed better protective effect than CSA on the fresh weight of aerial parts, twelve compounds exhibited better activity on the dry weight of aerial parts. Remarkably, two compounds (6Ih, 7II) had protective effect on the four aspects of TCM treated maize. Further antifungal assay showed their excellent activity against Physollospora piricola. The structure-activity relationships of CSA analogues as safeners and fungicides were discussed and it might be valuable for further molecular modification of new CSA analogues.

A rhenium-magnesium cocatalyzed [4+2] annulation of benzamides and alkynes via C-H/N-H functionalization is described. The reaction features a divergent and high level of diastereoselectivities, which are readily switchable by subtle tuning of reaction conditions. Thus, a wide range of both cis- and trans-3,4-dihydroisoquinolinones is expediently synthesized in a highly atom-economical manner. Moreover, mechanistic studies unraveled a tandem mode of action between rhenium and magnesium in the catalytic cycles.

A variety of aryl bromides have been treated with Mg and then chloral, followed by tBuOCl and subsequently alcohols or amines to produce the corresponding aromatic esters or amides in good yields via the formation of aryl trichloromethyl ketones as intermediates. These reactions are examples of a transition-metal-free one-pot preparation of aromatic esters and amides from aryl bromides. Aryl bromides have been treated with Mg and then chloral, followed by tBuOCl or tBuOCl with I2 as an additive, and subsequently alcohols or amines to form the corresponding aromatic esters and aromatic amides via aryl trichloromethyl ketones as intermediates. Copyright

The copper-catalyzed N-methylation of amides and O-methylation of carboxylic acids by using peroxides as the methylating reagent are described. Various amides and carboxylic acids were methylated affording N-substituted amides and esters. Tentative mechanistic studies suggest that this reaction is likely to involve a radical process.

Go with the flow: A general approach for amide bond formation by way of a continuous-flow photochemical rearrangement of nitrones was described (see scheme). Simple aryl-alkyl amide bonds as well as complex peptide bonds were constructed efficiently with a residence time less than 20minutes. A tetrapeptide was synthesized in this way and the method could be applied to peptide fragment coupling. Copyright

An efficient oxidative desulfurisation of thioamides by CuBr/TBHP is reported. Thioamides containing alkyl or aryl on the nitrogen undergo desulfurisation and give amides with good yields. Thioamides not containing substituent on the nitrogen undergo desulfurisation and give 1,2,4-thiadiazoles in moderate to good yields.

A facile and highly efficient method for one-pot Beckmann rearrangement of ketoximes into N-substituted amides using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, ketoximes are refluxed with TsIm and Cs2CO3 in the presence of SiO2 as a recyclable catalyst in DMF affording the corresponding amides in high yields. This methodology is highly efficient and regioselective for various structurally diverse ketoximes including symmetrical and unsymmetrical as well as cyclic oximes. The results of quantum mechanical studies used to rationalize the experimental outcomes are discussed. Copyright Taylor & Francis Group, LLC.

(Chemical Equation Presented) Nickel-catalyzed aminocarbonylation of aryl halides is described. A well-defined air-stable nickel-phosphite catalytic system (Ni(OAc)2 · 4H2O/phosphite 1) effectively promoted the aminocarbonylation of

(Chemical Equation Presented) The first heterolytic and homolytic N(O)-NO2 bond dissociation energy scales of three types Y-nitro (Y = N, O) compounds and corresponding radical anions in acetonitrile were established by using titration calorimetry combined with relevant electrochemical data through proper thermodynamic cycles.

Palladium-catalyzed carbonylations of aryl triflates with a range of nucleophiles using Mo(CO)6 as a solid CO source were explored. The reactions proceeded smoothly providing moderate to good yields of the corresponding aryl amides, esters, or acylsulfonamides after only 20 min of microwave irradiation. The acyl transfer reagent 4-dimethylaminopyridine was found to promote some of the more difficult transformations.

Rates of thermal decomposition of title compounds have been measured using a static reaction system. They undergo a unimolecular first-order elimination to give arylnitrile and the corresponding substituted amides. The decomposition parallels that of N-arylidenamino cyclic amide. The relative elimination rates at 600 K were calculated. The kinetic data reveal that the electronic effects of substituents, such as methyl, phenyl, benzyl, and allyl groups, are associated with the opposing directions in which the lone pair of electrons on the nitrogen atom of the arylidene moiety is being delocalized.

A benzophenone derivative represented by the following formula: whereinR1 represents, for example, an optionally substituted heterocyclic group, or a substituted phenyl group; Z represents, for example, an alkylene group; R2 represents, for example, a carboxyl group optionally protected with alkyl;R3 represents, for example, an optionally protected hydroxyl group; R4 represents, for example, an optionally substituted cycloalkyloxy group; and R5 represents, for example, a hydrogen atom, ???or a salt thereof has anti-arthritic activity, inhibits bone destruction caused by arthritis, and provides high safety and excellent pharmacokinetics and thus is useful as therapeutic agent for arthritis. These compounds have inhibitory effect on AP-1 activity and are useful as preventive or therapeutic agent for diseases in which excessive expression of AP-1 is involved.

Twenty-seven 11C-labelled amides were synthesised using [11C]carbon monoxide in low concentrations, palladium(0), organohalides and amines in a small micro-autoclave (200 μL). The focus of the study was to improve the radiochemical yields in this palladium-mediated amide synthesis when employing less-reactive amines, such as methylamine, [(2R)-1-ethylpyrrolidin-2-yl]methylamine (40) and 2-(pyridin-2-yl)ethanamine (41). The radiochemical yields were improved when utilizing 1,2,2,6,6-pentamethylpiperidine (pempidine) in combination with the amine substrates. The 11C-labelled amides were obtained mostly in high radiochemical yields (in the range 16-94%) and the specific radioactivity varied between 650 and 1250GBq/μmol. 1-(1,3-Benzodioxol-5-yl[13C]carbonyl)piperidine (6a) was synthesised to verify the labelling position (δ = 169.8 ppm) using 13C NMR spectroscopy. The radiochemical purity of the target compounds was determined by analytical HPLC and exceeded 95%. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

The hydrolysis of 1-aryl-3-acyl-3-methyltriazenes in aqueous sulfuric acid si described.The 3-formyl derivative undergoes an acid-catalysed deacylation reaction, characterised by a monotonic rise in the pseudo-first-order rate constant ko with increasing acidity, solvent deuterium isotope effects, kH2SO4/kD2SO4, of 0.9 (at 0.95 mol dm-3 H2SO4) and 0.8 (at 2.85 mol dm-3 H2SO4) and an entropy of activation of -80 J mol-1 K-1.The 3-alkanoyl derivatives also undergo acid-catalysed decomposition involving cleavage of either the N3-C acyl bond or the N2-N3 triazene bond.Below 3 mol dm-3 H2SO4, only acyl bond cleavage is observed.At higher acidities the extent of N2-N3 bond cleavage increases.The reaction is characterised by (i) solvent deuterium isotope effects of ca. 0.6 at 2 and 5 mol dm-3 H2SO4 and ca. 0.4 at 8 mol dm-3 H2SO4, (ii) ΔS(excit.) values of -6.7 and 51 J mol-1 K-1 at 2 and 6.1 mol dm-3 H2SO4, respectively, (iii) Hammett ρ values for the substituent in the triazene N-aryl ring of -0.7 and -0.9 at 3 and 9 mol dm-3 H2SO4, respectively, and (iv) an increase in reactivity with electron donating ability of the alkyl substituent of the acyl group.The 3-trifluoroacetyl triazenes are subject to solvolysis of the neutral, as well as the protonated, substrate.The hydrolysis of the neutral substrate involves N-acyl bond cleavage and is characterised by a solvent deuterium isotope effect, kH2O/kD2O, of 2.4, and a Hammett ρ value of +0.8 for the substituent in the N-aryl ring.The reactivity of the neutral substrate diminishes with increasing acidity until 6 mol dm-3 H2SO4, beyond which acid-catalysed N-acyl bond cleavage predominates, for which the solvent isotope effect, kH2SO4/kD2SO4, is 0.8 and the Hammett ρ value -0.5.The 3-aroyl substrates suffer acid-catalysed decomposition, the extent of the N2-N3 bond cleavage process being greater than for the N-alkanoyl counterparts.The reactions are rationalised in terms of a process that involves pre-equilibrium protonation of the substrate either at the N1 triazene atom or the amide oxygen atom, followed by subsequent decomposition of the protonated substrate via either N3-C bond cleavage, involving attack of water at the amide carbonyl, or unimolecular N2-N3 bond cleavage.The relative extents of the N3-C and N2-N3 bond cleavage processes depend on the reactivity of the acyl group and the water acitivity; the higher the water activity and the more reactive the acyl group, the more deacylation is favoured.

A series of aromatic and aliphatic aldehydes was reacted with N-((p-nitrobenzenesulfonyl)oxy)methylamine in chloroform.Products resulting from both carbon migration and hydride migration to nitrogen were isolated.The ratios of carbon to hydride migration products were used to clarify the reaction mechanism.The results support a two-step process in which cationic carbon to nitrogen rearrangements is rate determining.

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N-Methyl-p-toluohydroxamic acid (6) reacts rapidly with phosphorus compounds XYPCl (X = Ph, Y = OEt and X,Y = OCH2CH2O) at -60 deg C in the presence of pyridine to give the PIII intermediates (7) which have been characterised by 1H, 13C, and 31P n. m. r. spectroscopy.The intermediates decompose at ambient temperatures with homolysis of the N-O bond to give the isomeric N-phosphine oxides (8), accompanied by varying amounts of O-phosphonylhydroxamic acids (9) N-methyl-4-toluamide, (4) and phosphoryl-radical related products.Evidence for a radical-cage process (at least in part) is obtained from 1H and 31P CIDNP studies.

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The ozonolysis of azoles was investigated, and the products formed via a 1,2-addition of ozone were the main ones obtained.In particular, 2,5-disubstituted oxazoles (2) were treated with an excess of an ozone-oxygen stream to give the corresponding acid anhydrides (6) quantitatively.This reaction should be useful for the preparation of mixed anhydrides (6) in good yield at low temperature.

The reaction of several N-methylhydroxamic acids with methane- and benzene-sulphinyl chloride is shown to give an isolatable O-sulphinylated intermediate (IV) below 0 deg C.The intermediates decompose at ambient temperatures with simultaneous N-O and S-O bond fission to give the isomeric N-acyl-N-methylsulphonamide (V) and N-methyl-O-sulphonylhydroxamic acid (VI) by in-cage and free pair radical recombination. 1H and 13C n.m.r. spectra show strong polarisations in both sulphonamide (V) and O-sulphonylhydroxamic acid (VI), indicating radical cage mechanisms.In addition, a strong e.s.r. signal was observed due to the N-acyl- N-methylnitroxyl radical (X).